1. Field of the Invention:
The present invention relates to a process for production of ferrite stainless steel sheets of thin guage, particularly ferrite stainless steel sheets having excellent workability with simplified production procedures.
2. Description of the Prior Art:
The conventional production process for ferrite stainless steel sheets, for example, SUS430 series comprises box annealing a hot rolled steel strip for 2 hours or longer at a temperature ranging from 800.degree. to 850.degree. C., or continuous annealing for a short period of time at a temperature ranging from 900.degree. to 1100.degree. C., cold rolling the annealed steel strip and final annealing. The technical significance of the annealing of hot rolled steel strips in the conventional art is that: (1) it can reduce the problem of ridging which usually occurs during the press forming of the sheet; (2) it can improve the deep-drawability of the sheet (the deep-drawability is commonly represented by r, and 1.0 or larger of r represents satisfactory deep-drawability); and (3) it can improve cold workability (the ferrite stainless steel "as-hot-rolled" is very hard and very difficult to perform cold rolling.).
Therefore, in the conventional arts of production of ferrite stainless steel sheets, the annealing of the hot rolled sheet has long been considered to be essential.